This special volume comprises revised versions of a selection of the papers that were presented at the 9th International Conference on the Practice and Theory of Automated Timetabling (PATAT) in Belfast between 10th and 13th August 2010. The PATAT conferences are held biennially and this is the second time that the Annals of Operations Research has provided the venue for such a special collection of papers. The first PATAT special volume of this journal (Volume 194) contains papers associated with the 8th conference which was held in Montreal in 2008.

PATAT acts as an international forum for all aspects of timetabling, including educational timetabling, personnel rostering, sports timetabling, and transport scheduling. The conference series is particularly concerned both with closing the gap between timetabling theory and practice and with supporting multidisciplinary interactions. The collection of papers in this special volume reflect these aims. The conference in Belfast brought together approximately 100 participants from around the world. There were five plenary presentations, 74 standard talks, and 16 practitioner presentations. All the delegates were invited to submit their revised papers to this special volume. The papers have been through a rigorous and thorough review process, and we are delighted to be able to present the community with such an interesting and diverse selection of articles that reflect the latest thinking in timetabling research.

We would like to take this opportunity to thank all those who were responsible for the success of the conference. We would particularly like to thank Brian Fleming and all those within the School of Electronics, Electrical Engineering and Computer Science at the Queen’s University of Belfast who worked so hard before and during the conference.

We would also like to say thank you to the Steering and Programme Committees who all worked very hard to ensure the success of the conference and of this volume. The reviewers of the papers deserve a special mention. Finally, of course, thanks should go to all the authors and conference delegates. We are grateful for your support.